The Securities and Exchange Commission on Friday accused unnamed traders of raking in approximately US$4.6-million in potentially illegal profits by using foreign accounts to trade on inside knowledge of a buyout offer for drugmaker Onyx Pharmaceuticals Inc

NEW YORK — The Securities and Exchange Commission on Friday accused unnamed traders of raking in approximately US$4.6-million in potentially illegal profits by using foreign accounts to trade on inside knowledge of a buyout offer for drugmaker Onyx Pharmaceuticals Inc.

Onyx said Sunday that it rejected an offer from Amgen Inc. to buy it for US$120 per share because it “significantly undervalued” the company. Onyx said it would seek other suitors.

The US$120 offer price represented a 38% premium to Onyx’s closing price on Friday, and the stock spiked more than 50% after the rejection was made public.

The SEC said in a complaint filed in the U.S. District Court for the Southern District of New York that certain traders caused a “highly suspicious” spike in the volume of Onyx call options in the three trading days before the buyout offer was made public.

Call options are derivatives that give the holder the right to purchase certain shares at a set price for a certain period of time. In its complaint, the SEC noted that in general, one buys a call option, or call, when a stock price is expected to rise, and sells a call when the stock price is expected to fall.

The complaint alleges that the traders, as a result of their well-timed trades, collectively earned a profit of approximately US$4.6-million in just three days, and they had material nonpublic information about the offer at the time they purchased the call options that fueled their gains.

It notes that prior to the three days before the offer was made public, there was little trading in Onyx call options. The regulator said the timing and size of the options trades “were highly suspicious because they constituted large increases over the historical volume for those call options purchased.”

The SEC obtained an emergency court order to freeze the assets of traders using foreign accounts related to transactions in Onyx call options and prohibits the traders from destroying any evidence.

The regulator said the traders used omnibus accounts at Citigroup Global Markets and Barclays Capital, and the traders or the accounts are located in the Canary Islands and Beirut.